Full Excitation of Molecular Vibration Modes

1. The problem statement, all variables and given/known data
Given the relationship Cp/R as a function of Temperature, approximate the number of fully excited vibration modes at a given temperature for a given molecule.

2. The attempt at a solution
I have looked through several text books and many web sites, but I can't find this type of problem discussed anywhere. vaguely similar problems I have found only assume given excitation states. It seems like a relatively obscure problem, but I assume there is a generic solution process.